Generally, a well-known fixing device used for an image forming device includes a heating roller heated by an internal heat source, a press roller for holding a recording sheet together with the heating roller, and a peeling claw facing the heating roller to peel off the recording sheet from the heating roller.
The fixing device feeds the recording sheet onto which a toner image has been transferred, holding the recording sheet between the heating roller and the press roller, to thermally fix the toner image onto the recording sheet. When the recording sheet having the toner image thereon is stuck to the cylindrical surface of the heating roller, the peeling claw is used to peel off the recording sheet from the surface of the heating roller.
When the recording sheet is jammed near the peeling claw, the jammed recording sheet frequently presses the peeling claw to the heating roller, which may cause damage on the cylindrical surface of the heating roller. In order to avoid the damage, Japanese Patent Application Publication S61-200564 discloses a peeling device in which the leading edge of the peeling claw is displaceably supported to the frame to remove away from the heating roller when the peeling claw is pressed by the jammed recording sheet. According to this configuration, even if the peeling claw is pressed by the jammed recording sheet, the leading edge of the peeling claw is moved away from the heating roller, thereby preventing any damage of the heating roller.
However, even if the above configuration is employed, the leading edge of the peeling claw is not always moved away from the heating roller, depending on the posture and/or the number of the recording sheets jammed near the peeling claw. In this case, the leading edge of the peeling claw may be forced to strongly press the heating roller, thereby causing damage thereto.
Therefore, an object of the present invention is to provide a fixing device which reliably prevents damage of the heating roller which may caused by the jammed recording paper jam.